Cold-Curing Polyurethane Encapsulant for Durable High-Voltage Cable Joint Protection
In high-voltage cable systems, the joint is often the point where reliability is won or lost. Moisture, contamination and mechanical stress can undermine insulation and shorten service life. For cable-accessory manufacturers and power project contractors, choosing a sealant that cures reliably and stays flexible in real field conditions is a critical specification decision. Hunan Shangyu Waterproof Material Co., Ltd. has focused on this challenge since its establishment in Liling in October 2018, following its relocation from Shanghai. The company develops, produces and sells SY series two-component polyurethane sealant for high-voltage cable joints and accessories.
A Sealant Built for High-Voltage Cable Joints
The SY series is a two-part polyurethane system supplied as Part A and Part B. Part A is a buff, sticky thick liquid; Part B is a black, sticky thick liquid. When mixed thoroughly and poured into the cable protection shell, the material cures at normal ambient temperature into a rubber-like elastomer. This cold-application process avoids the need for hot-pour equipment and supports safer, more convenient installation in the field.
The system is designed to fill, seal and insulate high-voltage cable joints. Its cured elastomer helps block moisture ingress and provides electrical insulation, mechanical buffering and long-term protection for cable accessories. In the referenced product data sheet, the mix ratio is stated as B:A = 2:1, and the mixture is poured into the cable protection shell after uniform mixing.
Key Performance Features for Demanding Installations
Reliable electrical insulation. Available grades list breakdown voltage values of at least 15 kV/mm to 20 kV/mm, depending on the formulation. This helps cable-accessory makers meet insulation requirements in high-voltage joint designs.
High elongation and tensile strength. Data sheets for the standard and flame-retardant grades show elongation at break of at least 200% and tensile strength of 1.2–1.5 MPa. The cured sealant can accommodate cable movement, thermal cycling and mechanical stress without losing its protective function.
Climate and aging resistance. The material is formulated for cold and heat resistance and durable aging performance. This makes it suitable for projects in different regional climates, from hot and humid areas to cold and dry environments.
Watertight sealing. The product is listed as impermeable under a 0.3 MPa, 30-minute watertightness test. Water absorption is no more than 4% in the available data. These properties help protect joints from moisture-driven insulation failure.
Flame-retardant grade available. In addition to the standard SY high-voltage cable joint sealant, the company offers an environmentally friendly flame-retardant grade with fire-retardant additives. It is an option for cable-accessory projects that require added fire safety.
Export-friendly handling. The product is classified in its documentation as non-dangerous, stable, non-flammable and non-explosive, and can be transported as normal goods. Sealed metal pails support storage and distribution. Store in a cool, well-ventilated warehouse, away from direct sunlight and rain, and reseal Part A after opening to prevent curing.
Typical Technical Profile
Available SY grades show Shore A hardness around 50, tensile strength of 1.2–1.5 MPa, elongation at break of at least 200%, water absorption of no more than 4%, and breakdown voltage of 15–20 kV/mm depending on grade. The data sheet also lists watertight performance under 0.3 MPa for 30 minutes. Final properties depend on the selected product version and should be confirmed against the current technical data sheet for your project.
Applications and Installation Scenarios
SY high-voltage cable joint sealant is used in cable joints, cable accessories and protection shells in power transmission and distribution systems. Typical applications include underground and outdoor cable joints, substations, industrial power facilities and cable-accessory production. The material is suitable for projects where joints must resist moisture, thermal aging and mechanical stress over time.
For best results, the joint area should be clean and dry. Mix Part A and Part B thoroughly in the specified ratio, pour the mixture into the cable protection shell, and allow it to cure at normal ambient temperature. The installation environment should be dry and well ventilated. Part A should be resealed immediately after use if any material remains; otherwise it can cure and become unusable.
Manufacturing and Quality Support
Hunan Shangyu Waterproof Material Co., Ltd. operates as a specialized manufacturer integrating research, production and sales of high-voltage cable joint sealing materials. The company draws on design concepts from well-known Japanese, American and German brands and combines them with its own production experience. It develops formulations to address customer-specific needs and different regional climates. The product label indicates that the quality management system conforms to GB/T 19001-2016 / ISO 9001:2015.
The company has established cooperation with dozens of listed companies in the cable and cable-accessory industry in China. Its products are exported to the United States, India, Ukraine, Saudi Arabia and African countries. This export experience supports overseas buyers with product data and order communication for cable-accessory and power projects.
Industry Insight: Why Joint Sealing Deserves More Attention
As power networks expand, cable accessories are becoming more specialized and the demands on joint sealing are increasing. The joint is a composite structure, and the sealant is the barrier between the cable insulation and the external environment. A properly selected and applied sealant helps reduce moisture ingress, partial discharge risk and maintenance calls. Buyers should compare not only initial appearance but also cured elongation, tensile strength, electrical breakdown performance, watertightness and aging behavior. Equally important is process control: correct mix ratio, dry surfaces, thorough mixing and proper storage all influence final performance.
Partner with Hunan Shangyu
If you are sourcing high-voltage cable joint sealant for cable accessories, distribution, or project supply, Hunan Shangyu is ready to discuss your requirements. The company can provide product data, grade selection guidance and sample evaluation support for qualified buyers.
Contact: Hunan Shangyu Waterproof Material Co., Ltd.
Address: Beside Guoci Road, Liling Economic Development Zone, Hunan, 412200
Phone: 13386069160
Landline / Fax: 073122971118
Email: 249150783@qq.com
Website: http://www.shangyu-waterproof.com/
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